com.appland.appmap.output.v1.Parameters Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of appmap-agent Show documentation
Show all versions of appmap-agent Show documentation
Inspect and record the execution of Java for use with App Land
The newest version!
package com.appland.appmap.output.v1;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import org.tinylog.TaggedLogger;
import com.appland.appmap.config.AppMapConfig;
import com.appland.appmap.config.Properties;
import com.appland.appmap.util.Logger;
import javassist.CtBehavior;
import javassist.CtClass;
import javassist.NotFoundException;
import javassist.bytecode.CodeAttribute;
import javassist.bytecode.LocalVariableAttribute;
import javassist.bytecode.MethodInfo;
/**
* A serializable list of named and typed objects.
*
* @see Event
* @see Value
* @see GitHub: AppMap - Parameter object format
*/
public class Parameters implements Iterable {
private static final TaggedLogger logger = AppMapConfig.getLogger(null);
private final ArrayList values = new ArrayList();
public Parameters() { }
/**
* Constructs a Parameters object from an existing CtBehavior. Values will automatically be added,
* named and typed after the behaviors parameters.
*
* @param behavior The behavior to construct Parameters from
* @throws NoSourceAvailableException If parameter names cannot be read from the behavior
* @see GitHub: AppMap - Function call attributes
*/
public Parameters(CtBehavior behavior) {
MethodInfo methodInfo = behavior.getMethodInfo();
String fqn = behavior.getDeclaringClass().getName() +
"." + behavior.getName() +
methodInfo.getDescriptor();
CtClass[] paramTypes = null;
try {
paramTypes = behavior.getParameterTypes();
} catch (NotFoundException e) {
//@formatter:off
// getParameterTypes throws NotFoundException when it can't find a class
// definition for the type of one of the parameters. Given that:
//
// * the method represented by this behavior was loaded from one of the
// app's classes (and so originally compiled successfully)
//
// * the JVM resolves the classes for a method's parameters before
// loading the method itself
//
// this failure can only happen if we're trying to instrument a method
// that can never be called.
//
// Log a message and bail.
//@formatter:on
logger.debug(e, "Failed to get parameter types for {}", fqn);
return;
}
CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
LocalVariableAttribute locals = null;
if (codeAttribute != null) {
locals = (LocalVariableAttribute) codeAttribute.getAttribute(javassist.bytecode.LocalVariableAttribute.tag);
} else {
logger.debug("No code attribute for {}", fqn);
}
String[] paramNames = null;
int numParams = paramTypes.length;
if (locals != null && numParams > 0) {
int numLocals = locals.tableLength();
// This is handy when debugging this code, but produces too much
// noise for general use.
if (Properties.DebugLocals) {
Logger.println("local variables for " + fqn);
for (int idx = 0; idx < numLocals; idx++) {
Logger.printf(" %d %s %d\n", idx, locals.variableName(idx), locals.index(idx));
}
}
paramNames = new String[numParams];
Boolean isStatic = (behavior.getModifiers() & Modifier.STATIC) != 0;
int firstParamIdx = isStatic ? 0 : 1; // ignore `this`
int localVarIdx = 0;
// Scan the local variables until we find the one with an index
// that matches the first parameter index.
//
// In some cases, though, there aren't local variables for the
// parameters. For example, the class file for
// org.springframework.samples.petclinic.owner.PetTypeFormatter,
// has the method
// print(Ljava/lang/Object;Ljava/util/Locale;)Ljava/lang/String
// in it, which only has a local variable for `this`. This
// method isn't in the source file, so I'm not sure where it's
// coming from.
for (; localVarIdx < numLocals; localVarIdx++) {
if (locals.index(localVarIdx) == firstParamIdx) {
break;
}
}
if (localVarIdx < numLocals) {
// Assume the rest of the parameters follow the first.
paramNames[0] = locals.variableName(localVarIdx);
for (int idx = 1; idx < numParams; idx++) {
paramNames[idx] = locals.variableName(localVarIdx + idx);
}
}
}
Value[] paramValues = new Value[numParams];
for (int i = 0; i < paramTypes.length; ++i) {
// Use a real parameter name if we have it, a fake one if we
// don't.
String paramName = paramNames != null ? paramNames[i] : "p" + i;
Value param = new Value()
.setClassType(paramTypes[i].getName())
.setName(paramName)
.setKind("req");
paramValues[i] = param;
}
for (int i = 0; i < paramValues.length; ++i) {
this.add(paramValues[i]);
}
}
/**
* Get an iterator for each {@link Value}.
* @return A {@link Value} iterator
*/
@Override
public Iterator iterator() {
return this.values.iterator();
}
/**
* Add a new {@link Value} object to the end of the list.
* @param param The {@link Value} to be added
*/
public boolean add(Value param) {
if (param == null) {
return false;
}
return this.values.add(param);
}
/**
* Gets a stream of Values.
* @return A {@link Value} Stream
*/
public Stream stream() {
return this.values.stream();
}
/**
* Gets the number of values stored.
* @return The size of the internal value array
*/
public int size() {
return this.values.size();
}
/**
* Clears the internal value array.
*/
public void clear() {
this.values.clear();
}
/**
* Gets a {@Value} object stored by this Parameters object by name/identifier.
* @param name The name or identifier of the @{link Value} to be returned
* @return The {@link Value} object found
* @throws NoSuchElementException If no @{link Value} object is found
*/
public Value get(String name) throws NoSuchElementException {
if (this.values != null) {
for (Value param : this.values) {
if (param.name.equals(name)) {
return param;
}
}
}
throw new NoSuchElementException();
}
/**
* Gets a {@Value} object stored by this Parameters object by index.
* @param index The index of the @{link Value} to be returned
* @return The {@link Value} object at the given index
* @throws NoSuchElementException if no @{link Value} object is found at the given index
*/
public Value get(Integer index) throws NoSuchElementException {
if (this.values == null) {
throw new NoSuchElementException();
}
try {
return this.values.get(index);
} catch (NullPointerException | IndexOutOfBoundsException e) {
throw new NoSuchElementException();
}
}
/**
* Tests if the {@link Value} object at the given index is of a given type.
* @param index The index to validate
* @param type The name of the type to check for
* @return {@code true} if the @{link Value} at the given index matches the type given. Otherwise,
* {@code false}.
*/
public Boolean validate(Integer index, String type) {
try {
Value param = this.get(index);
return param.classType.equals(type);
} catch (NoSuchElementException e) {
return false;
}
}
/**
* Performs a deep copy of the Parameters object and all of its values.
* @return A new Parameters object
*/
public Parameters clone() {
Parameters clonedParams = new Parameters();
for (Value param : this.values) {
clonedParams.add(new Value(param));
}
return clonedParams;
}
@Override
public String toString() {
return this.values
.stream()
.map(value -> value.classType)
.collect(Collectors.joining(", "));
}
}